of the message. Its value must not be zero. See also &%final_timeout%&.
-.option dkim_domain smtp string&!! unset
+.option dkim_domain smtp string list&!! unset
.option dkim_selector smtp string&!! unset
.option dkim_private_key smtp string&!! unset
.option dkim_canon smtp string&!! unset
Signing is enabled by setting private options on the SMTP transport.
These options take (expandable) strings as arguments.
-.option dkim_domain smtp string&!! unset
-MANDATORY:
-The domain you want to sign with. The result of this expanded
-option is put into the &%$dkim_domain%& expansion variable.
+.option dkim_domain smtp string list&!! unset
+The domain(s) you want to sign with.
+.new
+After expansion, this can be a list.
+Each element in turn is put into the &%$dkim_domain%& expansion variable
+while expanding the remaining signing options.
+.wen
If it is empty after expansion, DKIM signing is not done.
.option dkim_selector smtp string&!! unset
-MANDATORY:
-This sets the key selector string. You can use the &%$dkim_domain%& expansion
-variable to look up a matching selector. The result is put in the expansion
+This sets the key selector string.
+You can use the &%$dkim_domain%& expansion variable to look up a matching selector.
+The result is put in the expansion
variable &%$dkim_selector%& which may be used in the &%dkim_private_key%&
option along with &%$dkim_domain%&.
+If the option is empty after expansion, DKIM signing is not done.
.option dkim_private_key smtp string&!! unset
-MANDATORY:
-This sets the private key to use. You can use the &%$dkim_domain%& and
+This sets the private key to use.
+You can use the &%$dkim_domain%& and
&%$dkim_selector%& expansion variables to determine the private key to use.
The result can either
.ilist
be signed. This case will not result in an error, even if &%dkim_strict%&
is set.
.endlist
+If the option is empty after expansion, DKIM signing is not done.
.option dkim_canon smtp string&!! unset
-OPTIONAL:
This option sets the canonicalization method used when signing a message.
The DKIM RFC currently supports two methods: "simple" and "relaxed".
The option defaults to "relaxed" when unset. Note: the current implementation
only supports using the same canonicalization method for both headers and body.
.option dkim_strict smtp string&!! unset
-OPTIONAL:
This option defines how Exim behaves when signing a message that
should be signed fails for some reason. When the expansion evaluates to
either "1" or "true", Exim will defer. Otherwise Exim will send the message
variables here.
.option dkim_sign_headers smtp string&!! unset
-OPTIONAL:
-When set, this option must expand to (or be specified as) a colon-separated
+If set, this option must expand to (or be specified as) a colon-separated
list of header names. Headers with these names will be included in the message
-signature. When unspecified, the header names recommended in RFC4871 will be
-used.
+signature.
+When unspecified, the header names recommended in RFC4871 will be used.
.section "Verifying DKIM signatures in incoming mail" "SECID514"